Brad,

With a single plane manifold, the same exact thing happens with the 2-1 firing pulse i nthe front of the motor between the banks, the cylinder drawing first has the advantage over the second pulse because the momentum is already moving in the earlier port.

I would liken it to a Bernouli effect so the "band Aid" is to first make sure the plenum is charged (which is is at it's optimum RPM) and the second is to help the second port pulse get more of a shot at the good charge.

But I think whenever the manifold is tuned and the Peak torque is matched well to the heads and induction , the plenum receives a charge which is the best guarantee all the cylinders are filling,

I used to modify Street Dominators by making the second port entry from the plenum more Trapezoidal (I used to call it "Gumby's head" lol) when looking at them side by side and with slightly more square area to the second port. It's seemed to work because the SD would usually pick up 1.5 MPH and drop the ET .1-.2 tenths on a typical low 12-high 11 B or E body.

Most recently I modded a Victor 340 in a similar way and it too picked up in terms of performance.

Interesting thread